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More Significant December Snowfalls

December 16, 2016

More Significant December Snowfalls:

A slow moving low pressure system brought another significant snowfall to the state this week over December 10-12. Many climate observers reported a storm total of 5 to 12 inches, and some daily snowfall records were set within the statewide observation network.

In addition to the added snow cover, the trend for below normal temperatures has continued this week, now 9 consecutive days across most of the state. This is the longest spell of cooler than normal temperatures since mid-February of 2015. Some northern Minnesota climate stations fell to -20°F or colder this week, including Georgetown (Clay County), Orr (St Louis County), and Camp Norris (Lake of the Woods County).

Snow cover around the state ranges from as little as 2 inches to over 12 inches in many northern counties. Despite the snow cover, frost depths in the soil have progressed over the past week and now range from 6 to 12 inches in most areas. Ice cover on area lakes is increasing as well with reports ranging mostly from 2 to 4 inches, but caution is still advised not to venture out on the ice yet.

Still, another significant snowfall is expected this weekend, this time with dangerous wind chill conditions and the coldest temperatures of the season. At least the outlook favors moderating temperatures for Christmas week and then the rest of the month.

New Seasonal Climate Outlooks:

The NOAA-Climate Prediction Center released new seasonal climate outlooks on Thursday (Dec 15) of this week. The outlooks favor cooler than normal temperatures for most of Minnesota over the January through March period. The outlooks also favor wetter than normal as well, although primarily in the northern portions of the state, where a snowier winter looks probable.

Weekly Weather Potpourri:

At the AGU Annual Meeting in San Francisco this week NOAA scientists presented a climate report card for trends in the Arctic Region. The report states that the Arctic region is warming at twice the rate of the rest of the planet. Spring snow cover is diminished and rapid melting of the Greenland ice sheet continues.

NOAA's Climate.Gov web site features an interesting article this week on studies of extreme weather event attribution and whether or not there are links to climate change. The article by Rebecca Lindsey dissects the process that scientists use to study the causes of weather and climate extremes. The article addresses some important questions for city managers and local units of government to consider.

David Schmidt from the University of Minnesota Department of Bioproducts and Biosystems Engineering pointed out two new information resources that may be useful to those working in agriculture and natural resource management. The first is a publication by the USDA entitled "Adaptation Resources for Agriculture", a 72 page document that covers climate adaptation in both cropping systems and animal agriculture systems. The second publication is also from the USDA and is titled "Adapting to a Changing Climate: A Planning Guide" and it is tailored to specific strategies in adapting animal systems to the changing climate. This guide is 20 pages long.

Another article this week from Nexus Media presents the case for using historical data and past responses to weather and climate extremes as a context for convincing conservative on climate that consideration of adaptation and mitigation strategies relative to climate change is time well spent. This article is written by Marlene Cimons.

An interesting study on satellite detection of soil moisture conditions was presented at the AGU (American Geophysical Union) Annual Meeting in San Francisco this week. Apparently satellite detection of soil moisture extremes (areas of drought and areas of super saturation) provides a good indicator of where power outages are likely to occur following severe storms. According to one of the authors, Steven Quiring of Ohio State University, the reasoning goes like this...."We see increased numbers of outages at both ends of the spectrum -- wherever soils are too wet or too dry,"......Drought makes tree branches more likely to snap off, and over-saturation makes trees more likely to be uprooted." Thus, satellite assessment of soil moisture may be routinely used in anticipating the location potential of power outages when storms occur. You can read at the Science Daily web site.

MPR listener question:

I wait for the school bus in the morning with my son who is in 4th grade. He is complaining about the sub-zero temperatures in the morning and I told him that in my day we had to wait for the bus in many more sub-zero mornings than he has to put up with today. At least that is my perception. Am I correct?

Answer:

So far we have recorded 4 subzero F morning readings this month in the Twin Cities Metro area. Given the forecast, we will have at least two more by early next week, for a total of six. Historically we have had Decembers that deliver up to 19 subzero F minimum temperatures (1876 and 1886), and conversely 14 Decembers, mostly recently last year have brought no subzero temperature readings in the month of December (recall last December was the warmest in state history).

Overall the number of subzero F temperature readings in the Twin Cities over the heating season (Nov-Mar) has ranged from 50 in 2013-2014 to just 2 in 2001-2002. The 145-year average is 28 days, but the trend is downward. The average for the decades of the 1950s, 1960s, and 1970s was 31 days, and the average since 1991 was only been 20 days. So you are correct to tell your son that you put up with more of them.

Twin Cities Almanac for December 16th:

The average MSP high temperature for this date is 27 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 12 degrees F (plus or minus 13 degrees F standard deviation).

Average dew point for December 16th is 9 degrees F, with a maximum of 43 degrees F in 2001 and a minimum of -25 degrees F in 1963.

All-time state records for December 16th:

The state record high temperature for this date is 65 degrees F at St Peter (Nicollet County) in 1939. The state record low temperature for this date is -39 degrees F at Pokegama Dam (Itasca County) in 1903. State record precipitation for this date is 2.57 inches at Gunflint Lake (Cook County) in 1984; and record snowfall is 14.0 inches at Farmington (Dakota County) in 1940.

Past Weather Features:

By far the warmest December 16th in state history occurred in 1939. In the absence of snow and with bright sunshine and a southerly wind daytime temperatures soared into the 50s F across most of the state. It was 55°F at Moorhead and 51°F at Grand Rapids. Further south 18 climate stations reported a high temperature in the 60s F. December of 1939 was the warmest in state history until last year, which set a new record.

A major winter storm dropped 4 to 14 inches of snowfall across the southern two-thirds of Minnesota over December 15-16, 1940. Schools were closed on Monday, the 16th in many southern Minnesota communities where snow drifted up to 4-5 feet.

December 16, 1963 was the coldest in state history with subzero temperature readings blanketing the entire landscape. Over 70 climate stations reported morning lows of -20°F or colder, and 20 stations reported -30°F or colder. The high temperature never rose above -10°F at Campbell (Wilkin County).

A large, slow moving winter storm brought heavy mixed precipitation to the state over December 14-16, 1984. Many communities reported 1-2 inches of precipitation in the form of rain, sleet, and snow. Isle right near Lake Mille Lacs reported 3.39 inches, a huge amount for December.

Outlook:

Windy and cold over the weekend with blowing snow and dangerous wind chill values. Heaviest snow will be in southern parts of the state and could approach 10 or more inches. Very cold on Sunday, with temperatures remaining subzero all day in many areas. Moderation in temperatures will start on Monday with slight changes for snow. Temperatures will climb to normal levels or slightly above next week, ending the prolonged Cold Wave.